KR20010095444A - Water repellent composition - Google Patents

Abstract

PURPOSE: Provided is a water repellent composition used for porous building material, which is excellent in repellent property and permeative property against porous inorganic material and absorptivity for water, sulfuric acid solution, and caustic soda solution. CONSTITUTION: The water repellent composition comprises: 10-30pts.wt. of a polysiloxane resin having trimethyl silyl(R3Si0.5, R is C1-C8 alkyl) units and SiO2 units in the molar ratio of 0.3-0.9:1; 65-85pts.wt. of a polydimethyl siloxane resin of which the both terminals are blocked off by alkyl alkoxy silyl groups; 1-5pts.wt. of a polydimethyl siloxane resin with a hydroxy terminal; 0.5-5.0pts.wt. of tin ester-based condensing catalyst; 0.1-0.5pts.wt. of a silane coupling agent.

Description

Water repellent composition

The present invention relates to a water repellent composition, and more particularly, to provide a building water repellent composition excellent in water repellency and permeability to a porous building material.

Organosilicon compounds are widely used as materials for imparting water repellency to porous inorganic compounds such as blocks, concrete, stones, tiles, plasters, glass, and metal materials. However, the organosilicon compounds known to date may penetrate partly to the object for imparting water repellency, leave stickiness on the surface of the object, or cause late contamination and adhesion of dust or foreign matter to the surface of the uncured organosilicon compound. There is a problem that causes. In this way, if pollution is caused, it may result in damage to the aesthetics of the building after a certain period of time or significantly reduce water repellency.

Construction water repellents that are widely used to date are as follows.

First, there are silane compounds. The compound has a hydrolyzable reactor in the molecule, which shows water repellency through a chemical change process in which the alkoxysilane is converted into a siloxane. However, in order to change to siloxane, temperature and moisture must be controlled within a predetermined range, and an alkaline component is required. If these conditions are not met, the alkoxysilane component is volatilized before curing, resulting in a decrease in water repellency and permeability.

Second, there is a siliconate system. This compound is a silane salt-like compound. When the surface is coated in the form of a powder, an aqueous solution, or the like, the compound reacts with carbonic acid gas in the air to form siloxane, thereby showing water repellency. Although this compound is easy to dilute with water and has a good quick beed, the siloxane powder that has penetrated when treated on the outer wall of the building is eluted and causes a whitening phenomenon.

Third, as a polysiloxane, the compound has already formed a siloxane chain, so that the water repellency immediately appears after the solvent is volatilized after treatment. However, when the siloxane condensation reaction is not sufficient, there is a fear that the water repellency may penetrate into the system and disappear.

In addition, US Pat. No. 2,412,470 discloses a method of imparting water repellency by coating a mixture of trimethylsilicon chloride and silicon tetrachloride directly on an inorganic compound surface. And US Pat. No. 2,672,455, which discloses a molar ratio of titanium tetraalkoxide Ti (OR) 4 (where R is an alkyl and alkylene radical or monocyclicaryl radical having less than 4 carbon atoms) 15-50%, trimethylsiloxane units and SiO 2 units. Methyl polysiloxane copolymer 5-70% of a silicone resin having a 1.0 to 2.5: 1, general formula R'nSiO (4-n) / 2 (R 'is a C1-C4 alkyl, alkylene or aryl radical) There is provided a water repellent agent for leather, consisting of 15-80% of the organosilicon compound represented.

By the way, the above-mentioned water repellents are excellent in water repellency on the surface of the building, but the disadvantage is that the permeability is not sufficient. In order to solve this problem, Korean Patent Publication No. 97-42929 provides a mixed composition of alkyl trialkoxy silane and oligomeric siloxane as a water repellent, and Korean Patent Publication Nos. 91-4587 and 94-38159 provide oligomers. Provided is a method for producing a permeable water repellent, which is composed mainly of soluble organosiloxane, polymethylhydrogen and fume silica.

However, the above-mentioned methods have disadvantages that the water repellency and permeability are not satisfactory, or there is a risk of generating hydrogen during distribution or poor storage stability.

Korean Patent Publication No. 96-22927 discloses 1,1,1-trimethoxy-3-aryl-silabutane, methyltrimethoxysilane and N- (2-aminoethyl) -3-aminopropyl trimethoxysilane A method for producing a water-soluble water repellent containing the above is disclosed. According to this method, not only water repellency and permeability are sufficient, but also it is difficult to obtain a sila compound commercially.

The technical problem to be achieved by the present invention is to solve the above problems to provide a water repellent composition with improved water repellency and permeability.

In order to achieve the above technical problem, in the present invention, 10 to 30 parts by weight of polysiloxane resin having a molar ratio of trimethylsilyl (R ₃ Si _0.5 , R is an alkyl group of C 1 -C 8) unit and SiO ₂ unit of 0.3 to 0.9: 1, both ends 65 to 85 parts by weight of a polydimethylsiloxane resin encapsulated with the alkylalkoxysilyl group, 1 to 5 parts by weight of a hydroxyl terminal polydimethylsiloxane resin, 0.5 to 5.0 parts by weight of a tin ester-based condensation catalyst, and 0.1 to 0.5 parts by weight of a silane coupling agent. Provide a water repellent composition.

The water repellent composition of the present invention is a polysiloxane resin having a molar ratio of trimethylsilyl (R ₃ Si _0.5 , R is an alkyl group of C 1 -C 8) unit and SiO ₂ unit of 0.3 to 0.9: 1, and a polydimethyl end group sealed with an alkylalkoxysilyl group. A siloxane resin, a hydroxyl terminal terminal polydimethylsiloxane resin, a tin ester type condensation catalyst, and a silane coupling agent are contained. In some cases, a diluent or a solvent may be further added to the composition to adjust the concentration of the composition. Herein, mineral oil or the like is used as a diluent or a solvent.

The polysiloxane resin having a molar ratio of trimethylsilyl (R ₃ Si _0.5 , R is an alkyl group of C 1 -C 8) unit and SiO ₂ unit of 0.3 to 0.9: 1 is represented by the following Chemical Formula 1, and the content thereof is 10 to 30 parts by weight. . If less than 10 parts by weight, curing is not sufficient, and if more than 30 parts by weight, permeability is not sufficient, which is not preferable.

R _m Si (OR ¹ ) _n O _{(4-n) / 2}

Wherein m is 0, 1 or 2, n is 1, 2 or 3, the sum of m and n is 1, 2 or 3, R ¹ is an alkyl group having 1 to 2 carbon atoms, and R is 1 carbon atom To alkyl group of 8; Preferably, R ¹ is a methyl group, R is an alkyl group having 1 to 6 carbon atoms.

Preferably, the polydimethylsiloxane resin whose terminal is sealed with the alkylalkoxysilyl group is represented by the formula (2). And the content of this resin is 65 to 85 parts by weight. If it is less than 65 parts by weight, the water repellency is not sufficient, and if it is more than 85 parts by weight, the curability is not sufficient, which is not preferable.

(R ² O) _k R ³ _(3-k) SiO [(CH ₃ ) ₂ SiO] _x SiR ³ _(3-k) (OR ² ) _k

Wherein k is 2 or 3, x is an integer of 10 to 200, R ² is an alkyl group having 1 to 2 carbon atoms, R ³ is an alkyl group having 1 to 17 carbon atoms or perfluorinated having 1 to 17 carbon atoms Alkyl group. Preferably, R ³ is methyl group, ethyl group, propyl group, isobutyl group, hexyl group, phenyl group, octyl group, dodecyl group, trifluoropropyl group and the like, and R ² is methoxy group, ethoxy group and the like.

The polydimethylsiloxane resin represented by Chemical Formula 2 is synthesized according to the following Scheme 1 as a linear polymer compound. As can be seen with reference to Scheme 1, the polydimethylsiloxane resin of the formula (2) is the reaction product of the alkyl alkoxysilane (A) and the polydimethylsiloxane (B) having a hydroxyl group at the end of the sock.

(R ² O) _{(k + 1)} R ³ _(3-K) Si + HO-[(CH ₃ ) ₂ SiO] _x -H →

(A) (B)

(R ² O) _k R ³ _(3-K) SiO [(CH ₃ ) ₂ SiO] _x SiR ³ _(3-k) (OR ² ) _k

<Formula 2>

In Scheme 1, the viscosity of the polydimethylsiloxane (B) is preferably 40 to 80 cps, because when the viscosity is out of the above range, the permeability and water repellency of the water repellent composition are slightly reduced.

The hydroxyl terminal terminal polydimethylsiloxane resin of the present invention has a penetration of 300 to 1200 mm / min, and preferably 400 to 600 mm / min. At this time, when the penetration degree of the hydroxyl terminal dimethylpolysiloxane resin is out of the above range, there is a problem that the water repellency (Quick beed) is lowered. And the content of the hydroxyl terminal polydimethylsiloxane resin is preferably 1 to 5 parts by weight. If the content of the hydroxyl-terminated polydimethylsiloxane resin is less than 1 part by weight, the water repellency is not sufficient, and if it exceeds 5 parts by weight, the permeability is lowered, which is not preferable.

The tin ester-based condensation catalyst performs a function of promoting the reaction between siloxanes, the content is 0.5 to 5.0 parts by weight. If it is less than 0.5 parts by weight, the curing is insufficient, and if it exceeds 5.0 parts by weight, the water repellency is lowered, which is not preferable. Specific examples of this condensation catalyst include dibutyl tin dilaurate, tin octoate, dimethyl tin dioctoate, dimethyl tin dibutyrate, tin butyrate, tin oleate, tin naphthenate, dimethyl tin dibenzoate Use one or more selected.

The silane coupling agent of the present invention performs a crosslinking function between the siloxane and the inorganic material, and the content of this compound is 0.1 to 0.5 parts by weight. If it is less than 0.1 part by weight, the siloxane crosslinking is insufficient, and if it exceeds 0.5 part by weight, the water repellency is lowered, which is not preferable. Specific examples of the silane coupling agent include 3-glycidoxypropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- ( Aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3- (2-imidazolin-yl) propyltriethoxysilane, 3-chloropropyltrimethoxysilane, Tris- [3- (trimethoxysilyl) propyl] isocyanurate, tris- [3- (triethoxysilyl) propyl] isocyanurate, tris- [3- (dimethoxysilyl) propyl] isocy One or more selected from anurates and tris [-3- (methyldimethoxysilyl) propyl] isocyanurate.

Hereinafter, the present invention will be described in detail with reference to the following Synthesis Examples and Examples, but the present invention is not limited to the following Examples.

Synthesis Example 1

Nitrogen gas was purged inside the three-necked flask, and then 1500 g of silanol-terminated polydimethylsiloxane (viscosity: 50 cps) was added thereto. Subsequently, the reaction mixture was heated to 40 ° C. and stirred, and a mixture of 118.6 g of methyltrimethoxysilane and 4.5 g of dibutylamine was added dropwise over 1 hour using a dropping funnel.

The reaction mixture was heated to 80 ° C. and stirred for 2 hours, and then cooled to 30 ° C. or less to synthesize polydimethylsiloxane in which both ends were sealed with methyldimethoxysilyl group.

Synthesis Example 2

A polydimethylsiloxane in which both ends were sealed with isobutyldimethoxysilyl group was synthesized in the same manner as in Synthesis Example 1, except that 157.7 g of isobutyltrimethoxysilane was used instead of 118.6 g of methyltrimethoxysilane. .

Synthesis Example 3

Except that 250.5 g of hexyltrimethoxysilane was used instead of 118.6 g of methyltrimethoxysilane, the same procedure as in Synthesis Example 1 was conducted to synthesize polydimethylsiloxane having both ends sealed with a hexyldimethoxysilyl group.

Synthesis Example 4

The same procedure as in Synthesis Example 1 was carried out except that 275.7 g of trifluoropropyltrimethoxysilane was used instead of 118.6 g of methyltrimethoxysilane, and both ends were blocked with trifluoropropyldimethoxysilyl group. The siloxanes were synthesized.

Synthesis Example 5

Silanol-terminated polydimethylsiloxane (viscosity: 700 cps) was used instead of silanol-terminated polydimethylsiloxane (viscosity: 50 cps), and the same procedure as in Synthesis Example 1 was performed except that the content of methyltrimethoxysilane was 91.2 g. It was carried out according to the synthesis of polydimethylsiloxane blocked at both ends of the hexyl dimethoxysilyl group.

Example 1

30 g of a polysiloxane resin having a molar ratio of _0.5 units of trimethylsilyl (CH ₃ ) ₃ Si and a SiO ₂ unit of 0.9: 1, and 65 g of polydimethylsiloxane in which the sock end obtained according to Synthesis Example 1 was sealed with methyldimethoxysilyl, 5 g of hydroxyl-terminated polydimethylsiloxane gum at 400 nm / min, 1 g of dibutyl tin diacetate and 0.5 g of 3-aminopropyltriethoxysilane were mixed and mineral oil was added thereto to make a water repellent composition. . At this time, the content of solids in the water repellent composition was adjusted to 5% by weight.

Example 2

In the same manner as in Example 1, except that polydimethylsiloxane having both ends of Synthesis Example 2 sealed with isobutyldimethoxysilyl group was used instead of polydimethylsiloxane having both ends of Synthesis Example 1 sealed with methyldimethoxysilyl group. Followed to make a water repellent composition.

Example 3

The same method as Example 1 except that both ends of Synthesis Example 1 used polydimethylsiloxane in which both ends were blocked with hexyldimethoxy group, instead of polydimethylsiloxane in which both ends were blocked with methyldimethoxysilyl group. It was carried out according to the method to make a water repellent composition.

Example 4

The same procedure as in Example 1 except that polydimethylsiloxane having both ends blocked with the trifluoropropyldimethoxysilyl group of Synthesis Example 4 was used instead of polydimethylsiloxane having both ends of Synthesis Example 1 blocked with the methyldimethoxysilyl group. It was carried out according to the method to make a water repellent composition.

Example 5

According to the same method as in Example 1, except that polydimethylsiloxane having both ends of Synthesis Example 5 sealed with dimethyldimethoxysilyl group was used instead of polydimethylsiloxane having both ends of Synthesis Example 1 sealed with methyldimethoxysilyl group. To obtain a water repellent composition.

Property evaluation method of the water repellent composition prepared according to Example 1-5 is as follows.

(1) water repellency

The test cement used to produce the specimens uses ordinary Portland cement specified in KS L5201 (Portland Cement), the sand used in the test uses sand specified in KS L5001 (Standard Yarn), and the water uses distilled water. .

First, 2000g of cement and 2000g of distilled water and 7500g of test sand are added and mixed well, and then it is put into a mold having a thickness of 60mm, 90mm in width and 190mm in length to make a specimen. Subsequently, after 48 hours, the mold was demolded and cured in a moisture content of 20 ± 3 ° C. and a relative humidity of 80% or more for 19 days.

On the surface of the specimen cured according to the method described above, the water repellent composition prepared according to Example 1-5 using a brush was evenly applied at a concentration of 500 g / m 2, and then left for 48 hours. The test is then carried out in accordance with the absorption test method of the cement waterproofing test for buildings specified in KS F 2451. The test results are made of three test specimens, each of which is expressed as an average of three times. The test specimens are immersed in water, sulfuric acid solution (hydrogen ion concentration, pH = 1), and caustic soda solution (hydrogen ion concentration, pH = 14). After that, the resultant was absorbed for 1 hour, 5 hours, 24 hours, 5 days and 10 days, and the absorption ratio was calculated and evaluated according to the following formula.

(2) permeability

Put the water-repellent composition prepared according to Example 1-5 on the front surface of the specimen in a mold having a thickness of 60mm, width 90mm, length 190mm using a brush evenly at a concentration of 500g / ㎡, temperature 20 ℃, relative humidity After curing for 48 hours at 50% RH, the specimens were divided in half. Permeability is assessed by measuring the depth of the layer that has not absorbed water by spraying water on a half-section of the specimen.

(3) water repellency

Put the water repellent composition prepared according to Example 1-4 and Comparative Example on the front of the specimen in a mold having a thickness of 60mm, 90mm, 190mm vertically using a brush at a concentration of 500g / ㎡, and this temperature 20 ℃ And cured for 48 hours at 50% RH. Then, dropping the water droplets using the eyedropper on the surface of the specimen to evaluate the degree of condensation in appearance. At this time, the contact angle of the water droplet is represented by ◎, relatively large by ○, and completely wet by ×.

In the case of using the water repellent composition according to Example 1-5, the water repellency, permeability and water repellency evaluation results are shown in Table 1 below.

* Untreated: It is a case where the water repellent composition application treatment is not performed.

As shown in Table 1, using the water repellent composition of Example 1-5, compared to the case of using the water repellent composition according to the comparative example was excellent in water repellency and permeability to inorganic materials such as concrete, water, sulfuric acid The absorption in the solution and caustic soda solution was also excellent.

The water repellent composition of the present invention has excellent water repellency and permeability with respect to porous inorganic materials, and is very suitable for construction because of excellent water absorption of water, sulfuric acid solution and caustic soda solution.

Claims (8)

10 to 30 parts by weight of a polysiloxane resin having a molar ratio of trimethylsilyl (R ₃ Si _0.5 , wherein R is an alkyl group of C 1 -C 8) unit and SiO ₂ unit of 0.3 to 0.9: 1, and polydimethylsiloxane having both ends sealed with an alkylalkoxysilyl group A water-repellent composition comprising 65 to 85 parts by weight of resin, 1 to 5 parts by weight of hydroxyl terminal polydimethylsiloxane resin, 0.5 to 5.0 parts by weight of tin ester-based condensation catalyst, and 0.1 to 0.5 parts by weight of silane coupling agent. The water repellent according to claim 1, wherein the polysiloxane resin having a molar ratio of the trimethylsilyl (R ₃ Si _0.5 , R is an alkyl group of C 1 -C 8) unit and a SiO ₂ unit is 0.3 to 0.9: 1. Composition. <Formula 1> R _m Si (OR ¹ ) _n O _{(4-n) / 2} Wherein m is 0, 1 or 2, n is 1, 2 or 3, the sum of m and n is 1, 2 or 3, R ¹ is an alkyl group having 1 to 2 carbon atoms, and R is 1 carbon atom To alkyl group of 8; The water-repellent composition according to claim 1, wherein the polydimethylsiloxane resin whose both ends are sealed with an alkylalkoxysilyl group is represented by the formula (2). <Formula 2> (R ² O) _k R ³ _(3-k) SiO [(CH ₃ ) ₂ SiO] _x SiR ³ _(3-k) (OR ² ) _k Wherein k is 2 or 3, x is an integer of 10 to 200, R ² is an alkyl group having 1 to 2 carbon atoms, R ³ is an alkyl group having 1 to 17 carbon atoms or perfluorinated having 1 to 17 carbon atoms Alkyl group. The water-repellent composition according to claim 3, wherein the polysiloxane resin of Chemical Formula 2 is a reaction product of alkylalkoxysilane (A) and polydimethylsiloxane (B) having hydroxyl groups at both ends. (R ² O) _{(k + 1)} R ³ _(3-K) Si + HO-[(CH ₃ ) ₂ SiO] _x -H → (A) (B) (R ² O) _k R ³ _(3-K) SiO [(CH ₃ ) ₂ SiO] _x SiR ³ _(3-k) (OR ² ) _k <Formula 2> The water-repellent composition according to claim 4, wherein the viscosity of the polydimethylsiloxane (B) having hydroxyl groups at both ends is 40 to 80 cps. The water-repellent composition according to claim 1, wherein the penetration of the hydroxyl terminal-end polydimethylsiloxane resin is 300 to 1200 mm / min. The tin ester-based condensation catalyst of claim 1, wherein the tin ester-based condensation catalyst is dibutyl tin dilaurate, tin octoate, dimethyl tin dioctoate, dimethyl tin dibutyrate, tin butyrate, tin oleate, tin naphthenate and dimethyl tin di. At least one selected from the group consisting of benzoates. The method of claim 1, wherein the silane coupling agent is 3-glycidoxypropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3- (2-imidazolin-yl) propyltriethoxysilane, 3-chloropropyltri Methoxysilane is tris- [3- (trimethoxysilyl) propyl] isocyanurate, tris- [3- (triethoxysilyl) propyl] isocyanurate, tris- [3- (dimethoxysilyl ) Propyl] isocyanurate and tris [-3- (methyldimethoxysilyl) propyl] isocyanurate at least one selected from the group consisting of a water repellent composition.